<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder="示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>
      <!-- 所属分类 TODO -->
      <el-form-item label="课程分类">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged">

          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>

        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>
      <!-- 课程讲师 TODO -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">

          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>
      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>
      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
        <Tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>
      <!-- <el-form-item label="课程简介">
        <el-input v-model="courseInfo.description" placeholder=" "/>
      </el-form-item> -->
      <!-- 课程封面 TODO -->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss/avatar'"
          class="avatar-uploader">
          <img :src="courseInfo.cover">
        </el-upload>
      </el-form-item>
      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>
      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="next">保存并下一步</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import Tinymce from '@/components/Tinymce'
import courseApi from '@/api/edu/course'
import subjectApi from '@/api/edu/subject'
export default {
  components: {
    Tinymce
  },
  data() {
    return {
      saveBtnDisabled: false,
      courseInfo: {
        title: '',
        subjectId: '', // 二级分类id
        subjectParentId: '', // 一级分类id
        teacherId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/01.jpg',
        price: 0
      },
      BASE_API: process.env.BASE_API, // 接口API地址
      teacherList: [], // 封装所有的讲师
      subjectOneList: [], // 一级分类
      subjectTwoList: [], // 二级分类
      courseId: ''
    }
  },
  created() {
    if (this.$route.params && this.$route.params.id) {
    // 表示从章节返回来的，进行数据回写到表单
      this.courseId = this.$route.params.id
      this.getCourseInfo(this.courseId)
    } else {
      // 初始化一级分类
      this.getOneSubject()
      // 初始化所有讲师
      this.getListTeacher()
      // 初始化表单数据
      this.initFormData()
    }
  },
  methods: {
    // 初始化表单数据
    initFormData() {
      this.courseInfo = {
        title: '',
        subjectId: '', // 二级分类id
        subjectParentId: '', // 一级分类id
        teacherId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/01.jpg',
        price: 0
      }
    },
    // 根据课程id获取基本信息:
    getCourseInfo(courseId) {
      courseApi.getCourseInfoById(courseId).then(res => {
        this.courseInfo = res.data.courseInfoVo
        // 数据回写，其中课程分类，讲师分类都是id,需要根据id查询出来，前端再次渲染
        subjectApi.getSubjectList().then(res1 => {
          const temp = res1.data.list
          // 课程分类的数据回写
          this.subjectOneList = temp
          console.log('temp:', temp)
          temp.map(item => {
            // 比较当前courseInfo里面一级分类id和所有的一级分类id
            if (this.courseInfo.subjectParentId === item.id) {
              this.subjectTwoList = item.children
            }
          })
        })
        // 讲师的数据回写
        this.getListTeacher()
      })
    },
    // 获取一级课程分类
    getOneSubject() {
      subjectApi.getSubjectList().then(res => {
        this.subjectOneList = res.data.list
      })
    },
    // 获取所有讲师
    getListTeacher() {
      courseApi.getListTeacher(this.courseInfo).then(res => {
        this.teacherList = res.data.items
      })
    },
    // 处理下一步
    next() {
      courseApi.addCourseInfo(this.courseInfo).then(res => {
        this.$message({
          type: 'success',
          message: '添加课程信息成功!'
        })
        // 跳转到第二步
        this.$router.push({ path: '/course/chapter/' + res.data.courseId })
      })
    },
    // 点击某个一级分类，触发change，显示对应二级分类
    subjectLevelOneChanged(value) {
      // value就是一级分类id值
      // 遍历所有的分类，包含一级和二级
      this.subjectOneList.map(item => {
        if (item.id === value) {
          this.subjectTwoList = item.children
          this.courseInfo.subjectId = ''
        }
      })
    },
    // 上传封面成功调用的方法
    handleAvatarSuccess(res, file) {
      this.courseInfo.cover = res.data.url
    },
    // 上传之前调用的方法
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    }
  }
}
</script>
